Such a testing device is known from Dutch Application 8,701,577. It is intended for testing the allergic reaction of the skin test subject to various test substances and test liquids. These test substances and test liquids are each accommodated in a compartment of the testing device, which can be applied by means of the adhesive strip to a specific position on the skin of a test subject. The test substances and test liquids are left to act on the skin for a predetermined period, e.g. 72 hours, following which the testing device is removed again.
Since the test substances and test liquids are held captive between the skin and the compartments in question during the test, the influence of the individual different substances can be determined accurately.
In practice, the known testing device is used as follows: First of all, the removable protective strip adhering to the adhesive strip is removed. The various test substances and test liquids are then placed in the compartments which have now become free, following which the whole combination is stuck on the skin of a test subject by means of the adhesive strip. In the process the test substances and test liquids in the compartments come into contact with the part of the skin which is covered by the compartment in question. This last factor is very important for accurately determining the influence on the skin of each of the various substances individually.
However, with the use of this known testing device the problem occurs that the placing of the test substances and test liquids in the compartments does not always take place equally accurately, owing to the inaccuracy of the metering devices/hypodermic needle holders for the substances and phials for the liquids. The test substance or test liquid is sometimes spilled on the adhesive strip, as a result of which the allergic reaction does not remain limited to the "test area" and the adjacent skin can also be affected. If another substance also happens to be spilled on the adhesive strip, there is a risk of the various substances becoming mixed, which means that a reliable result can no longer be obtained. Besides, in such a case the test can no longer reasonably be carried out, because the adhesive layer of the plaster has lost its effectiveness.